Regional modelling of extreme sea levels induced by hurricanes

Abstract. Coastal zones are increasingly threatened by extreme sea level events. Storm surges are one of the most hazardous components of these extremes, especially in regions prone to tropical cyclones. This study aims to explore factors affecting the performance of numerical modelling in simulating storm surges in the tropical Atlantic region. The maxima, duration and time evolution of the extreme storm surge events are evaluated for four historical hurricanes by comparison against tide gauge records. The ADCIRC and NEMO ocean models are intercompared using a similar configuration in terms of domain, bathymetry and spatial resolution. These models are then used to perform sensitivity experiments on oceanic and atmospheric forcings, physical parameterizations for wind stress and baroclinic/barotropic modes. NEMO and ADCIRC show a similar skill to simulate storm surges induced by hurricanes. Storm surges simulated with ERA5 atmospheric reanalysis forcing are generally more accurate than those using parametric wind models for simulated hurricanes. The inclusion of the baroclinic processes improves storm surge amplitudes in some coastal locations such as along the southeastern Florida peninsula (USA). Experiments exploring different wind stress implementations and the interactions between storm surges, tides and mean sea level however have shown a minimal impact on storm surges induced by hurricanes.